KR820002400Y1 - Invertor device - Google Patents

Abstract

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Description

Inverter Device

1 is a circuit diagram showing a conventional inverter device.

2 is a diagram of a base input signal waveform of a transistor in a conventional inverter device.

3 is an output voltage waveform diagram of a conventional inverter device.

4 is a circuit diagram showing an embodiment of the present invention.

5 is an input signal waveform diagram of the base of the silist gate and the transistor.

6 is an output voltage waveform diagram.

The present invention relates to an inverting device, that is, an inverter device for converting direct current into alternating current.

1 is a view showing a conventional inverter device,

1, DC power

(2U +) (2V +) (2W +) and (2U-) (2V-) (2W-) are transistors,

(3U +) (3V +) (3W +) and (3U-) (3V-) (3W-) are diodes.

Of these diodes and transistors, transistor (2U +) and diode (3U +), transistor (2V +) and diode (3V +),. … The transistors 2W- and the diodes 3W- are connected in reverse parallel with each other, and the transistors 2U + and (2U-), the transistors 2V + and (2V-), and the transistors 2W + and (2W-), respectively. Are connected in series respectively, and the collectors of the transistors 2U + (2V +) and (2W +) are the positive electrode (+ pole) of the DC power supply 1, and the emi of the transistors 2U- (2V-) and (2W-), respectively. The rotor is connected to the negative electrode (-pole) of the DC power supply 1, respectively.

(4) is a load, the three terminals (U) (V) and (W) are connection points of transistors 2U + and (2U-) and connection points of transistors 2V + and (2V-),

And it is connected to the connection point of transistor 2W + and (2W-), respectively.

Transistor 2W + (2V +)... … Each base of (2W-) is connected to the base controller 5, respectively, so that the periods indicated by the above transistors in FIG. 2, that is, the transistors 2U +, 2V + and (2W +), are each 120 ° apart.

In addition, the transistors 2U + and (2U-), (2V +) and (2V-), (2W +) and (2W-) are delayed by 180 ° and controlled so that the base signal is turned on between 180 °. Configuration. Since the conventional inverter device is constructed as described above, when the base signal is input to each transistor, the voltage as shown in FIG. 3 appears between the terminals U, V, and W of the load 4.

If the voltage of the DC power supply 1 is now Ed, in the period of (I) shown in Fig. 2, the transistors 2U + (2W +) and (2V-) are turned on (terminals). (Ed) between)-(V), (-Ed) between terminals (V)-(W), and (0) voltage between terminals (W)-(V). This corresponds to the period (I) shown in FIG. In the period (II) shown in FIG. 2, the transistors 2U + (2V-) and (2W-) are turned on, so that between the terminals U and V (Ed), The low voltage of (Ed) comes out between (V)-(W) (0) and between terminals (W)-(U).

This corresponds to the period (II) shown in FIG. In this way, the alternating current is supplied from the direct current power source 1 to the load 4.

And diode (3U +) (3V +). … (3W +) is a transistor 2U + (2V +)... When the load is an inductive load. … Even if (2W-) is turned OFF, the diode is provided to form a path for raising the current in the direction in which the transistor is turned off. Thus, for example, when the transistor 2U + is turned off, the diode 2U- is turned off. The current flowing through the transistor 2U + flows, and the potential of the terminal U when the diode 3U- is turned on is exactly the same as when the transistor 2U- is turned on. There is no change in the voltage waveform under display.

In the conventional inverter device described above, a transistor is used as a switching element. However, this transistor is expensive in comparison with a thyristor that can be used as a switching element, but since the thyristor is not turned off even when the gate is turned off, the transistor is simply replaced by a thyristor. Since it is not possible to operate normally, the thyristor uses a current circuit, which is expensive.

This paper has been made in view of such a point, and when substituting a thyristor for a transistor, a transistor is used for the arc of this thyristor, and a cheap inverter is provided.

4 shows an embodiment of the present invention.

(1) is a first DC power source having a voltage Ed;

(2U +) (2V-)... … (2W-) is a thyristor,

(3U +) (3V +)... … (3W-) diode

(6 +) (6-) is a transistor, (7) is a resistor, and (8) is a second DC power source.

By the way, thyristors (2U +) and (2U-), (2V +) and (2V-), and (2W +) and (2W-) are connected in series, respectively, and the thyristors (2U +), (2V +) and (2W +) The anode is connected to the positive electrode of the first DC power supply 1 through the transistor 6+, respectively, and the cathodes of the thyristors 2U- (2V-) and (2W-) are made through the transistor 6-. It is connected to the negative electrode of the DC power supply 1 of 1, respectively.

On the other hand, the diodes 3U + and 3U- are connected in series with each other, and these connection points are connected to the connection points of the thyristors 2U + and 2U- and the terminals U of the load 4, respectively.

The diodes 3V + and 3V- are connected in series with each other, and their connection points are connected to the contacts of the thyristors 2W + and 2W- and the terminals V of the load 4, respectively.

The diodes 3W + and 3W- are also connected in series with each other, and their connection points are connected to the contacts of the thyristors 2W + and 2W- and the terminals W of the load 4.

Again, the cathodes of diodes 3U + (3V-) and (3W +) are connected to the positive electrodes of the first DC power supply 1, respectively, and the anodes of diodes 3U (3V) and (3W-) are the first direct current. It is connected to the negative electrode of the power supply 1, respectively.

Next, the positive electrode of the second DC power supply 8 directly connected to the resistor 7 is connected to the cathodes of the thyristors 2U- (2V-) and (2W-), and the other end of the resistor 7 is connected to the thyristor. It is connected to the anodes of (2U +) (2V +) and (2W +), respectively.

Since the inverter device of the present invention is constructed as above, the thyristor (2U +) (2V-). … Signals as shown in FIG. 5 are input to the (2V−) (2W +) and the transistors 6+ and (6-).

That is, thyristors (2U +) (2V +) and (2W +) receive signals that are delayed by 120 ° from each other, and the thyristors (2W +), (2U-), (2V +), (2V-), (2W +), and (2W-). Signals delayed by 180 ° are input to each.

The signal widths are all 180 °.

However, one transistor 6+ has a signal for turning off the input signals of the thyristors 2U + (2V +) and (2W +) for only 50 占 sec, while the other transistor 6- has a thyristor 2U. -) (2V-) and (2W-) input signals are turned off and at the same time the signal is turned off for only 50μsec.

Next, thyristor subheading is performed in the following manner.

That is, in FIG. 4, first, the thyristor 2U + is extinguished with the gate signal of the thyristor 2U + turned off and the base signal of the transistor 6+ turned off.

At this time, the transistor 6+ is turned off immediately, and the current flowing in the thyristor 2U + is also zero.

However, since the thyristor does not apply the reverse voltage even if the current is 0, the time until the off function can be maintained (turn off time) becomes long, so that the reverse voltage is applied to the second DC power source 8.

That is, the voltage of the second DC power source 8 is applied to the cathode of the thyristor 2U- through the transistor 6- and the diode 3U- at the positive electrode and at the negative electrode of the second DC power source 8. Pass the resistor (7) to the anode of the thyristor (2U-).

In this current path, the reverse voltage is applied to the thyristors 2U +, but no current flows, so even if the value of the resistor 7 is increased, there is no harm in applying the reverse voltage.

In addition, the voltage of the second DC power source 8 is optimally about 10V. In addition, since the voltages of the first and second DC power supplies 1 and 8 are applied to the resistor 7 when the transistors 6+ and 6- 6 are turned on, the resistor 7 is preferably around several hundred Ω.

In the case where the load 4 is an inductive load, the current flowing through the thyristor 2U + so far flows through the diode 3U− as in the case of FIG.

At the timing of extinguishing the thyristor 2U +, when the gate signal is input to the thyristor 2V + and the transistor 6+ is turned off, the current flowing through the thyristor 2V + is also turned off, but there is no problem because it is a short time.

Next, when the thyristor 2U- is extinguished, the gate signal of the thyristor 2U- is cut off and the base signal of the transistor 6 is turned off, and the voltage of the second DC power supply 8 is changed from the positive electrode to the thyristor 2U. The anode of thyristor 2U is applied to the cathode of-) and through the resistor 7, the transistor 6+, and the diode 3U + at the negative electrode of the second DC power source 8.

However, in this case, when the load 4 is an inductive load, the current flowing in the thyristor 2U- flows in the diode 3U +. In this way, thyristor (2U +) (2V +)... … By operating (2W-) and transistors 6+ and (6-), the voltage shown in FIG. 6 is obtained between the terminals of the load 4.

That is, the period of I shown in FIG. 5 is because the thyristor 2U + (2V-) (2W +) and the transistors 6+ and 6- are on, so that the voltage between the terminals U and V is The voltage between (Ed) and the terminals (V)-(W) becomes (-Ed) and the voltage between the terminals (W)-(U) becomes zero.

However, the first 50 μsec of this period is the same as the thyristor (2V-) is off because the transistor (6-) is off, and between each terminal (U)-(V), between (V)-(W) and ( All voltages between W)-(U) become zero.

In addition, since voltage can be irradiated in the (II)-(V) period shown in FIG. 5, the voltage waveform shown in FIG. 6 is obtained as a result.

In the above-described one embodiment (FIG. 4), for example, a chopper and a gate turn-off thyristor may be used as the switching element instead of the transistors 6+ and 6-, as shown in FIG. The embodiment shows a three-phase circuit but can also be implemented in a single phase or other parallel circuit.

As described above, according to the present invention, a single transistor is disposed in front of several thyristors and the transistor is turned off to automatically apply a reverse voltage to the thyristors so that the thyristors are turned off, thereby reducing the use of expensive transistors. And it has the excellent effect of providing the inverter device at low cost.

In addition, since the second DC power supply 8 for applying the reverse voltage to the thyristor can be made small, the inverter device according to the present invention is not costly up.

Claims (1)

Diode group (3U +) connected in series between the positive electrode and the negative electrode of the first DC power source 1. … In parallel connection of (3W-) to the first DC power supply 1, the first and second switching elements 6+ ( Thyristors group 2U +, which are connected in series and are connected at the same time between the resistor 7 and the direct heating element of the second DC power supply 8 between the two switching elements 6+ and 6-. … And (2W-) so that a forward voltage is applied from the first DC power source (1).